Wide use of computers and the Internet in recent years has encouraged use of e-mail as a medium for exchange of information. In particular, information providers (or other information administrators) often use e-mail to distribute information to its members having membership. For example, the patent literature PTL 1 discloses an e-mail delivery device configured and adapted to deliver e-mail to registered users, which are the members having the membership, the e-mail being created by the information provider and containing addresses of information service websites.